Earnings per Share - EPS Reconciliation (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Income from continuing operations	$ 7.7	$ 1.7	$ 10.1	$ 11.8
Less: Allocation to participating securities	(0.2)	(0.1)	(0.3)	(0.5)
Income from continuing operations allocated to common stockholders	7.5	1.6	9.8	11.3
(Loss) income from discontinued operations, net of tax	(0.2)	(0.2)	(0.1)	3.0
Less: Allocation to participating securities	0	0	0	(0.1)
(Loss) income from discontinued operations allocated to common stockholders	(0.2)	(0.2)	(0.1)	2.9
Diluted net income	7.5	1.5	10.0	14.8
Less: Allocation to participating securities	(0.2)	(0.1)	(0.3)	(0.6)
Diluted net income allocated to common stockholders	$ 7.3	$ 1.4	$ 9.7	$ 14.2
Weighted average number of common shares outstanding	18,609,550	18,380,971	18,627,383	18,327,517
Share-based awards	345,578	453,621	646,770	494,282
Diluted weighted-average shares	18,955,128	18,834,592	19,274,153	18,821,799